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Measuring temperature
For this project, you will need an Arduino UNO,
an LM35 or TMP36 temperature sensor, an LDR, a
breadboard, a two 1k resistors and a few jumper wires.
For measuring temperature I picked the very
common LM35 sensor. This low cost sensor is rated to
operate between -55 and 150°C, with a +/- 0.5°C accuracy
(although it’s a little bit tricky to measure minus
temperatures with the LM35). The way this analog sensor
works is really simple and in fact, most analog sensors
work in a similar way. First they are powered from a
constant power source on two of their pins (+ and -),
then, on a third pin, they output a lower voltage value
that is directly proportional to the sensor reading.
Our temperature sensor will be powered from
the Arduino UNO’s 5V pin and will output voltage
values between 0 volts and 2 volts, changing with
the temperature. The LM35’s scale factor is 0.01V/°C,
meaning that 1 celsius degrees change in the air
temperature will result in a 0.01 volt change on the
output pin.
Conveniently, the Arduino’s analog input pins
are designed to measure and convert voltage into data we